Using AWS CloudHSM KeyStore Java class

The AWS CloudHSM KeyStore class provides a special-purpose PKCS12 key store. This key store can store certificates along with your key data and correlate them to key data stored on AWS CloudHSM. The AWS CloudHSM KeyStore class implements the KeyStore Service Provider Interface (SPI) of the Java Cryptography Extension (JCE). For more information about using KeyStore, see Class KeyStore.

Note

Because certificates are public information, and to maximize storage capacity for cryptographic keys, AWS CloudHSM does not support storing certificates on HSMs.

Choosing the appropriate key store

The AWS CloudHSM Java Cryptographic Extension (JCE) provider offers a special-purpose AWS CloudHSM KeyStore. The AWS CloudHSM KeyStore class supports offloading key operations to the HSM, local storage of certificates and certificate-based operations.

Load the special-purpose CloudHSM KeyStore as follows:

KeyStore ks = KeyStore.getInstance("CloudHSM")

Initializing AWS CloudHSM KeyStore

Log into the AWS CloudHSM KeyStore the same way that you log into the JCE provider. You can use either environment variables or the system property file, and you should log in before you start using the CloudHSM KeyStore. For an example of logging into an HSM using the JCE provider, see Login to an HSM.

If desired, you can specify a password to encrypt the local PKCS12 file which holds key store data. When you create the AWS CloudHSM Keystore, you set the password and provide it when using the load, set and get methods.

Instantiate a new CloudHSM KeyStore object as follows:

ks.load(null, null);

Write keystore data to a file using the store method. From that point on, you can load the existing keystore using the load method with the source file and password as follows:

ks.load(inputStream, password);

Using AWS CloudHSM KeyStore

AWS CloudHSM KeyStore complies with the JCE Class KeyStore specification and provides the following functions.

• load

  Loads the key store from the given input stream. If a password was set when saving the key store, this same password must be provided for the load to succeed. Set both parameters to null to initialize an new empty key store.

  KeyStore ks = KeyStore.getInstance("CloudHSM");
  ks.load(inputStream, password);

• aliases

  Returns an enumeration of the alias names of all entries in the given key store instance. Results include objects stored locally in the PKCS12 file and objects resident on the HSM.

  Sample code:

  KeyStore ks = KeyStore.getInstance("CloudHSM");
  for(Enumeration<String> entry = ks.aliases(); entry.hasMoreElements();) {    
      String label = entry.nextElement();    
      System.out.println(label);
  }

• containsalias

  Returns true if the key store has access to at least one object with the specified alias. The key store checks objects stored locally in the PKCS12 file and objects resident on the HSM.

• deleteEntry

  Deletes a certificate entry from the local PKCS12 file. Deleting key data stored in an HSM is not supported using the AWS CloudHSM KeyStore. You can delete keys using the destroy method of the Destroyable interface.

  ((Destroyable) key).destroy();

• getCertificate

  Returns the certificate associated with an alias if available. If the alias does not exist or references an object which is not a certificate, the function returns NULL.

  KeyStore ks = KeyStore.getInstance("CloudHSM");
  Certificate cert = ks.getCertificate(alias);

• getCertificateAlias

  Returns the name (alias) of the first key store entry whose data matches the given certificate.

  KeyStore ks = KeyStore.getInstance("CloudHSM");
  String alias = ks.getCertificateAlias(cert);

• getCertificateChain

  Returns the certificate chain associated with the given alias. If the alias does not exist or references an object which is not a certificate, the function returns NULL.

• getCreationDate

  Returns the creation date of the entry identified by the given alias. If a creation date is not available, the function returns the date on which the certificate became valid.

• getKey

  GetKey is passed to the HSM and returns a key object corresponding to the given label. As getKey directly queries the HSM, it can be used for any key on the HSM regardless of whether it was generated by the KeyStore.

  Key key = ks.getKey(keyLabel, null);

• isCertificateEntry

  Checks if the entry with the given alias represents a certificate entry.

• isKeyEntry

  Checks if the entry with the given alias represents a key entry. The action searches both the PKCS12 file and the HSM for the alias.

• setCertificateEntry

  Assigns the given certificate to the given alias. If the given alias is already being used to identify a key or certificate, a KeyStoreException is thrown. You can use JCE code to get the key object and then use the KeyStore SetKeyEntry method to associate the certificate to the key.

• setKeyEntry with byte[] key

  This API is currently unsupported with Client SDK 5.

• setKeyEntry with Key object

  Assigns the given key to the given alias and stores it inside the HSM. If the key does not already exist inside the HSM, it will be imported into the HSM as an extractable session key.

  If the Key object is of type PrivateKey, it must be accompanied by a corresponding certificate chain.

  If the alias already exists, the SetKeyEntry call throws a KeyStoreException and prevents the key from being overwritten. If the key must be overwritten, use KMU or JCE for that purpose.

• engineSize

  Returns the number of entries in the keystore.

• store

  Stores the key store to the given output stream as a PKCS12 file and secures it with the given password. In addition, it persists all loaded keys (which are set using setKey calls).